Preparation of disperse bisanil dyes derived from diaminomaleo-nitrile

ABSTRACT

Extremely bright, tinctorially strong disperse dyes derived from diaminomaleonitrile and selected aromatic and heterocyclic aldehydes, and their preparation, useful for dyeing and printing polyester and polyester-cotton blend fibers in yellow to blue shades of generally good fastness properties, which dyes are of the general formula

United States Patent Begland 1 Oct. 21, 1975 PREPARATION OF DISPERSEBISANIL 3.179692 4/1965 Martin 260/465 E UX DYES DERIVED FROM 3,221,04111/1965 Roland 260/465 E 3,657,213 4/1972 Ramanathan 260/465 E XDIAMINOMALEONITRILE 3,661,888 5/1972 Sagal 260/465 E x [75] Inventor;Robert Walter Begland, 3,717,625 2/1973 Peter 260/465 E X Wilmington, Dl 3,778,446 12/1973 Weigert 260/465 E X [73] Assignee: E. I. Du PontdeNemours and Primary Examiner A"en 3 Curtis Company, W1lm1ngt0n, Del.

[22] Filed: Jan. 3, 1974 1571 ABSTRACT [21] APPL NOJ 430,414 Extremelybright, tinctorially strong disperse dyes der1ved fromd1am1nomaleon1tr1le and selected aromat1c and heterocyclic aldehydes,and their preparation, 1 Cl 260/465 260/240 G; 260/465 D useful fordyeing and printing polyester and polyester- [51] hit. Cl. CO9B 55/00cotton blend fibers in yellow to blue shades of gener- [58] Fleld ofSearch 260/240 G, 465 E ally good fastness properties, which dyes are Ofthe general formula 56] References Cited A CH=N-C N =C N -N HA UNITEDSTATES PATENTS (C (C :C l 2 5001 3/1950 A h t I 260/ 40 G wherem Ar andAr are aromat1c or aromatlc-hke ms e a 2,766,243 10/1956 Middleton260/270 P x groups for example phenyl or pyndyl' 2,849,449 8/1958 Capeet al 260/240 G 3 Claims, N0 Drawings PREPARATION OF DISPERSE BISANILDYES DERIVED FROM DIAMINOMALEO-NITRILE BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to yellow to blue bisanildisperse dyes prepared from diaminomaleonitrile.

2. Description of the Prior Art l Monocondensation products ofdiaminomaleonitrile wherein Ar is either phenyl, p-dimethylaminophenylor furfuryl. Robertson and Vaughan in J. Am. Chem. Soc,

80, 2691 (1958) disclose yellow monocondensation products of suchformula wherein Ar is either phydroxyphenyl, p-nitrophenyl or cinnamyl.Reported attempts to introduce a second mole of the same aldehyde appearto have been unsuccessful and attempts to introduce a second mole of adifferent aldehyde with the monoanil (Schiff base) resulted indisplacement of the aldehyde residue of the original derivative. Suchdisplacement facilely occurred when the second aldehyde possessed acarbonyl carbon atom of greater electron deficiency than the originalaldehyde; for example, p-nitrobenzaldehyde benzaldehydep-hydroxybenzaldehyde (decreasing order of facility of displacement).Hinkel et al. in J. Chem. Soc., 1432(1937) disclose yellowmonocondensation products of such formula wherein Ar is either phenyl,p-anisyl, salicyl or mbromosalicyl. None of the aforementioned referencediscloses that the monoadducts of diaminomaleonitrile and aldehydes areuseful as dyestuffs for synthetic fibers, especially polyester fibers.

US. Pat. No. 2,200,689 discloses heterocyclic pyrazinocyanine pigmentdyestuffs which are obtainable by condensing diaminomaleonitrile with1,2-dicar- OBJECTS AND SUMMARY OF THE INVENTION The dye trade iscontinuously seeking new and better dyes for use in existing and newlydeveloped dyeing and printing systems and for use with fibers, blendedfibers and fabrics, which fabrics may, for example, be subjected to anafter-treatment (after-dyeing) step, such as the application of apermanent press resin composition, to impart a particularly desirableproperty to the dyed fabric. Dyes which combine brightness of shade andhigh tinctorial strength with good application and fastness propertiesare particularly useful in such systems. Bright dyes are more attractivethan dull dyes and offer greater versatility in formulating mixedshades. Commercial disperse dyes for use on polyester and othersynthetic and semi-synthetic fibers tend as a class to have rather dullshades. Bright disperse dyes often suffer from poor lightfastness orhigh cost, or both.

It is an object of this invention to provide yellow to blue dispersedyes. It is a further object to provide dyes which exhibit outstandingbrightness of shade and high tinctorial strength and which are generallyfluorescent and significantly brighter than known existing dispersedyes. It is a still further object to provide disperse dyes withacceptable fastness to light and sublimation on polyester andpolyester-cellulosic blend fibers. Yet another object is to provideeconomically attractive dyes derived from inexpensive startingmaterials. A further object is to provide a variety of processes forpreparing such dyes.

In summary, this invention relates to bisanil disperse dyes (and theirpreparation) of the formula Ar -CH- =NC(CN )=C(CN )N=CH-Ar wherein eachof Ar and Ar is independently selected from 1. benzo(5- and6-membered)heteroc yclic groups containing 04 methyl substituents and 2.phenyl, naphthyl, S-membered heterocyclic and 6-membered heterocyclicgroups containing 0-3 substituents selected from N0 halogen, CN, Calkyl, C ,alkoxy, OCH -phenyl, phenyl, CF OH, OC alkylene-N(C, ,alkyl) Calkylene-Cl, NHCONH NHCOA, NHSO A, SR SO R NHR NHCOC bonyl compounds,such as diacetyl, glyoxal, benzil, oralkylene-B and -NR R wherein:

R N cu R on wherein R is H, CH or phenyl with copper salts. The2,3-dicyanopyrazines can be prepared by condensation ofdiaminomaleonitrile with, respectively, glyoxal, diacetyl and benzil.

a. R is C alkyl or C alkylene-R b. R is C alkyl, C alkylene R or, if Aror Ar is phenyl, C alkylene attached to a phenyl position which is orthoto the position to which the nitrogen is attached;

0. R is CN, halogen, OH, phenyl, C alkoxy, 0G,. ,alkylene-CN, CO A,OCOA, OCONHA or CO C alkylene-OCOA;

d. R., is CN, halogen, OH, phenyl, OC alkylene-CN, CO A, OCOA, CO Calkylene-OCOA, SO A,,

phthalimido, succinimido, glutarimido, OCOCH=CH CH CH(OCOA)CH OA or CHCH(OCONHA)CH OA;

e. A is C alkyl or R f. B is halogen, C alkoxy or R g. R is phenylcontaining O-2 substituents selected from C alkyl, C alkoxy, halogen, N0CN, C alkylCONH and NR R wherein each of R and R is independentlyselected from H and C alkyl, with at least one of R and R being C alkyl;

and

h. R is C alkyl, C H OH, C cycloalkyl or R DETAILED DESCRIPTION OF THEINVENTION The bisanil dyes of the above formula can exist in twoisomeric forms, the cis arrangement Furthermore, the dyes can besymmetrical (if Ar and Ar are identical) or unsymmetrical (if Ar and Arare different). The dyes can be prepared by condensingdiaminomaleonitrile with the aldehydes Ar CHO and Ar CI-IO ashereinafter described, Ar CHO and Ar;,. CHO being the same or different.The present invention also relates to additional processes for preparingthe heretofore defined symmetrical and unsymmetrical, cisandtrans-bisanil dyes.

Diaminomaleonitrile is generally referred to as HCN tetramer since it isavailable in low yields from the base catalyzed tetramerization of HCNas shown in US. Pat. No. 2,499,441. Tetramerization of HCN todiaminomaleonitrile also occurs in the presence of a catalytic amount ofa basic catalyst and at least one of the cocatalystsdiiminosuccinonitrile or cyanogen as shown in US. Pat. No. 3,629,318.Tetramerization of HCN in an aprotic solvent, such as dimethylsulfoxide,in the presence of a catalyst, such as sodiumcyanide, at 6070C. atatmospheric pressure, as shown in US. Pat. No. 3,704,797, provides yetanother route to diaminomaleonitrile; such a procedure also is describedin Chemical Week, July 12, 1972, page 36 and in European Chemical News,Mar. 2, 1973, page 20. Diaminomaleonitrile also can be prepared fromdiiminosuccinonitrile which itself is preparable, according to J. Org.Chem., 37, 4133 (1972), in high yield by the base catalyzed addition ofHCN to cyanogen. Diiminosuccinonitrile can be converted by chemicalreagents to diaminomaleonitrile, for example, by reaction thereof withHCN as shown in US. Pat. No. 3,564,039. Diaminomaleonitrile also can beprepared by reaction of diiminosuccinonitrile with hydrogen in thepresence of a Group VIII transition metal hydrogenation catalyst asshown in US. Pat. No. 3,551,473.

The yellow to blue unsymmetrical bisanil disperse dyes can be preparedby condensing 1 mole of diaminomaleonitrile with 1 mole each ofdifferent aryl aldehydes Ar,CHO and Ar CHO. Symmetrical bisanil dyes canbe prepared by condensing 1 mole of diaminomaleonitrile with 2 moles ofa single aryl aldehyde.

Examples of aryl aldehydes, Ar,CHO and/or Ar CI-IO, which are useful inthe preparation of the bisanil dyes are given in Table I.

TABLE I 4-[N,N-bis( methyl )amino]benzaldehyde4-bromo-2,5-diisopropylbenzaldehyde 4-[ N,N-bis(rirpropyl)aminol-Lmethylbenzaldehyde 6-formyl-N-( methyl )-2,2,4,7-tetramethyl-l,2,3,4-tetrahydroquinoline 5-bromothiophene-2-carboxaldehyde4-[N-ethyl-N-(2-methoxycarbonylethyl )amino 1-2- methylbenzaldehyde4-[N-(2-butoxycarbonylethyl )-N-ethylamino]-2'- methylbenzaldehyde4-ethylcarbonylamidobenzaldehyde N-methylindole-3-carboxaldehyde4-thiomethoxybenzaldehyde 4-thio-n-butoxybenzaldehyde4-thiomethoxynaphthaldehyde 4-phenylsulfonylbenzaldehyde4-methylsulfonylbenzaldehyde 4-thio-( 2 -hydroxyethoxy )benzaldehydebenzaldehyde 4-(N-cyanoethyl-N-methylamino)benzaldehyde4-chlorobenzaldehyde 2,6-dichlorobenzaldehyde 2-nitrobenzaldehyde3-nitrobenzaldehyde 4-nitrobenzaldehyde 4-[N,N-bis( ethyl)amino]benzaldehyde 4-[N,N-bis(ethyl )amino]-2-hydroxybenzaldehyde3-hydroxybenzaldehyde 2-hydroxybenzaldehyde 4-hydroxybenzaldehyde 4-[N-cyanoethyl-N-ethylamino]-2-methylbenzaldehyde 4-[ N,N-bis(hydroxyethyl )amino]benzaldehyde 4-[N,N-bis( cyanoethyl)amino]benzaldehyde 4-[N,N-bis(n-propyl )amino]benzaldehyde3-chloro-4-hydroxy-5-methoxybenzaldehyde 4-chloro-3-nitrobenzaldehyde5-chIoro-2-nitrobenzaldehyde 3,4-dibenzyloxybenzaldehyde3,5-dibromosalicylaldehyde 3 ,5-di-tert.-butyl-4-hydroxybenzaldehyde4-[2-(diethylamino )-ethoxy]benzaldehyde 2,S-dihydroxybenzaldehyde3,4-dihydroxybenzaldehyde 2,3-dimethyl-4-methoxybenzaldehyde2,5-dimethyI-4-methoxybenzaldehyde 2,4-dimethylbenzaldehyde2,5-dimethylbenzaldehyde 2-ethoxybenzaldehyde 4-ethoxybenzaldehyde3-ethoxy-4-hydroxybenzaldehyde 4-cyanobenzaldehyde4-acetamidobenzaldehyde 2-methoxybenzaldehyde 3-methoxybenzaldehyde3-benzyloxybenzaldehyde 4-benzyloxybenzaldehyde 4-biphenylcarboxaldehyde5-bromo-2-methoxybenzaldehyde 2-bromobenzaldehyde 3-bromobenzaldehydeS-bromosalicylaldehyde5-bromovanillin[5-bromo-4-hydroxy-3-methoxybenzaldehyde]5-bromo-3,4-dimethoxybenzaldehyde 6-bromo-3,4-dimethoxybenzaldehyde2-(2-chloroethyl )benzaldehyde 2-chloro-6-fluorobenzaldehyde4-ethoxy-3-methoxybenzaldehyde 4- {N-[ 2-(3-cyanobenzoyloxyethoxycarbonyl )ethyl- ]amin}benzaldehyde 4-{N-[ 2-(2-methylbenzoyloxyethoxycarbonyl)ethyl lamino} benzaldehyde2chloro-4-{N-[ 2-(propionyloxyethoxycarbonyl )ethyl]amino}benzaldehyde4-{N,N-bis[ 2-(butyryloxyethoxycarbonyl )ethyl- ]amino}benzaldehyde4-{N-[2-(benzoyloxyethoxycarbonyl)ethyl ]-N- methylamino}benzaldehyde4-(N-cyanoethylamino)-3-n-butylbenzaldehyde 4'-[N,N-bis(ethyl)amino]-2'-( 3-methoxypropionamido )benzaldehyde2-acetamido-4'(N-cyanoethyl-N-ethylamino)benzaldehyde 2-butyramido-4-[N-cyanoethyl-N-( 2methoxycarbonylethyl)amino]benzaldehyde 2-(3-chloropropionamido)-4'-[N-phenethyl-N-npropylamino1benzaldehyde2'-acetamido-4'-[N-( 2-methoxycarbonylethyl- )amino]-'-methoxybenzaldehyde 4'-[N,N-bis(ethyl)amino]-5 '-methoxy-2'-(3-methylbenzamido)benzaldehyde 2-chloroacetamido-4- N ,N-bis( ethyl)amino]-5 methoxybenzaldehyde 2-(3-chlorobutyramido)-4'-[N,N-bis(cyanoethyl- )amino ]-5-methoxybenzaldehyde2'-acetamido-4-[N,N-bis(2-acetoxyethoxycarbonylethyl )amino1-5'-methoxybenzaldehyde 4-[N,N-bis(2-acetoxyethyl)amino]-2'-( 2-chlorobenzamido)-5 '-methoxybenzaldehyde 2-acetamido-4'-[N-(Z-acetoxyethyl )-N-cyanoethylamino -5 -methoxybenzaldehyde4-[N-cyanoethyl-N-ethylamino]-5 '-methoxy-2 4- nitrobenzamido)benzaldehyde 4'-[N-( 2-methoxycarbonylethyl )-N-methylamino]-benzaldehyde 4'-[N,N-bis(2-acetoxyethyl)amino]-2'-methylsul- Ifonamidobenzaldehyde 4'-[ N-(2-acetoxyethyl)-N-cyanoethylamino1-2-phenylsulfonamidobenzaldehyde 4'-[N,N-bis(2-acetoxyethyl)amino]-5-methoxy-2' methylsulfonamidobenzaldehyde 4-[N-ethyl-N-(2-succinimidoethyl)amino]-2- methylbenzaldehyde 4'-[N-ethyl-N-(2-phthalimidoethyl)amino]-2- methylbenzaldehyde 4-[N-cyanoethyl-N-(2-succinimidoethyl)amino]-2'- methylbenzaldehyde 4-[N-ethyl-N-(2-glutarimidoethyl )amino]-2- methylbenzaldehyde6-formyl-N-(B-phenylcarbamoyloxyethyl)-2,2,4,7-

tetramethyll ,2,3,4-tetrahydroquinoline6-formyl-N-cyanoethyl-2,2,4,7-tetramethyl-l ,2,3,4-

tetrahydroquinoline 6-formyl-N-(B-acetoxyethyl )-2,2,4,7-tetramethyl-1,2,3 ,4-tetrahydroquinoline 6-formyl-N-(B-benzoyloxyethyl)-2,2,4,7-tetramethyl-l ,2,3,4-tetrahydroquinoline 4-[ N,N-bis(Z-cyanoethylethoxyethyl )amino]-2- methylbenzaldehyde 2-acetamido-4-[N-( 2-cyanoethylethoxyethyl )-N- ethylamino]benzaldehyde 84-[N-ethyl-N-(Z-methylsulfonylethyl)amino]-2'- methylbenzaldehyde4-[N-cyanoethyl-N-(Z-phenylsulfonylethyl)amino]- benzaldehyde4-[N-cyanoethyl-N-(2-methoxyethylamino1benzaldehyde4-[N-ethyl-N-(2-propionoxyethyl)amino]-2- 'methylbenzaldehydeindole-Z-carboxaldehyde N-ethylindole-3-carboxaldehydeN-(2-acetoxyethyl)indole-3-carboxaldehyde thianaphthene-Z-carboxaldehydethianaphthene-3-carboxaldehyde 4,5-dibromothiophene-2-carboxaldehyde4-bromothiophene-2-carboxaldehyde thiophene-3-carboxaldehyde5-[N,N-bis(ethyl)aminolindole-3-carboxaldehyde5-[N,N-bis(ethyl)amino]thiophene-2-carboxaldehyde 5-[N,N-bis( methyl)amino]-l ,3,4-thiadiazole-2-carboxaldehyde 5-[N,N-bis( ethyl )amino]-l,4-thiazole-2-carboxaldehyde 4-bromofuran-Z-carboxaldehydepyridine-N-oxide-3-carboxaldehyde The aldehydes listed above are eithercommercially available or can be prepared by well known prior artprocedures, such as the Vilsmeier reaction using dimethylformamide,phosphorus oxychloride and the appropriate substituted aryl compound.

Further to the above, the aryl aldehydes can be moditied by theincorporation of sulfonic acid groups (SO l-l) to provide, whencondensed with diaminomaleonitrile as described herein, acid dyesforpotential use on nylon. Similarly, incorporation of basic groups (-N(alkyl) can provide cationic dyes having potential utility onpolyacrylonitrile and acid-modified polyester and polyamide fibers.

The symmetrical dyes, that is, bisanil dyes of the above formula whereinAr and Ar are the same, can be prepared in one step by condensing 1 moleof diaminomaleonitrile with 2 moles of an aryl aldehyde, in the presenceof an acidic catalyst, in an organic solvent, at 50l50C., whilecontinuously removing the water formed during the reaction either byazeotropic distillation or by the action of a dehydrating agent, such asphosphorus pentoxide or dicyclohexylcarbodiimide. Preferred catalysts inthe condensation include sulfuric acid, polyphosphoric acid andp-toluenesulfonic acid. Organic solvents, such as acetonitrile,tetrahydrofuran, dimethylformamide, hexamethylphosphoramide,dimethylacetamide, toluene, xylene, benzene and monochlorobenzene areequally useful. After cooling the reaction mixture to room temperature,the precipitated bisanil dyestuff can be isolated by filtration.

It has been discovered that condensation of 2 moles of4-[N,N-bis(ethyl)amino]benzaldehyde and 1 mole of diaminomaleonitrile at505 5C. in hexamethylphosphoramide containing sulfuric acid as catalyst,in the presence of phosphorus pentoxide to remove;the water of reaction,over a 6 hour period, provides'the bright, fluorescent, red cis-bisanildye N,N-{4-[N,N- bis(ethyl)amino]benzylidene}diaminomaleonitrile havingthe structure The cis geometry about the central carbon-carbon doublebond is evidenced by the large observed dipole moment (14.6 D) of thisdye. This resultcorrelates well with the large dipole moment (7.8 D) ofdiaminomaleonitrile as reported by Webb et al. in J. Am. Chem. Soc., 77,3491-3 (1955). Depending on the rotation of the amino groups, a muchlower dipole moment is predicted for the trans configuration. Ingeneral, the cis-symmetrical bisanil dyes prepared by the aforementionedprocess undergo isomerization and/or partial hydrolysis upon attemptedrecrystallization from dimethylformamide, acetonitrile or nitromethane,yielding mixtures of the cisand trans-symmetrical bisanils and theyellow monoanil species.

A useful one-step process for the preparation of symmetrical bisanildyes involves the condensation of at least about 2 moles of arylaldehyde with 1 mole of diaminomaleonitrile in glacial acetic acid, atabout the boiling temperature of the acid, for extended periods of time.This process provides the thermodynamically more stable trans isomerhaving the structure The low dipole moment of 3.2D on this productsupports the structure assignment. Reaction times of up to eludemonochlorobenzene, acetonitrile, dimethylformamide, isopropanol,dichloroethane, toluene and benzene, the latter being most useful. Byway of example of the stepwise condensation, diaminomaleonitrile (1mole) is condensed with 4-[N,N-bis(ethyl)amino]benzaldehyde (1 mole) intetrahydrofuran, in the presence of sulfuric acid, at 60-65C., for 3hours; a high yield, for example, 80-90%, of the yellow monoanil N- {4-[N,N-bis(ethyl)amino]benzylidine}diaminomaleonitrile is obtained. Thisintermediate monoanil possesses inherent deficiencies in applicationproperties on polyester when compared to the bisanil. The monoanils, ingeneral, also do not exhibit the fluorescence and brightness which arecharacteristic of the bisanil derivatives of diaminomaleonitrile.Subsequent condensation of the aforesaid monoanil (1 mole) with 2 molesof 4-chlorobenzaldehyde in benzene, in the presence of a catalyticamount of piperidine, at 7580C., while continuously azeotroping waterover a six-hour period, provides, after removal of solvent, a -50% yieldof the trans-unsymmetrical bisanil N-{4-[N,N-bis(ethyl-)amino]benzylidene -N(4-chlorobenzylidene) diaminomaleonitrile havingthe structure about 4 hours at ll5-l20C. generally are adequate forobtaining substantially trans isomer. Upon cooling to room temperature,the trans-bisanil crystallizes and can be isolated from the acid medium.Yields of 60-75% of high purity symmetrical trans-bisanils can beobtained by this procedure. A similar result can be obtained bycondensing 1 mole of the monoanil of diaminomaleonitrile with 1 mole ofan aryl aldehyde under similar conditions to those described above.

The unsymmetrical bisanil dyes, that is, bisanil dyes prepared fromdiaminomaleonitrile and two different aldehydes, can be prepared instepwise fashion by monocondensation of 1 mole of a first aryl aldehydewith 1 mole of diaminomaleonitrile to provide the yellow monoanilderivative. The monocondensation is preferably run in an organicsolvent, such as tetrahydrofuran, acetonitrile or benzene, for up toabout 4 hours, at the boiling point of the solvent, in the presence ofan acidic catalyst, such as sulfuric acid. the resultant yellow monoanil(1 mole) is then treated with 2 moles of a different aryl aldehyde in anorganic sovlent in the presence of a secondary or tertiary aminecatalyst, while azeotropically removing the water formed in thecondensation. Preferred amine catalysts are piperidine andtriethylenediamine. No condensation occurs in the absence of catalyst.Useful organic solvents in- When the amount of basic catalyst is lessthan 0.50 mole per mole of monoanil, the trans-unsymmetrical 5 dye iscontaminated with the cis-unsymmetrical dye and both the cis and transforms of the symmetrical adduct N,N-{4-[N,N-bis(ethyl)amino]benzylidene}diaminomaleonitrile. The latter derivative is believed to beformed by initial hydrolysis of N-{4-[N,N-bis(ethyl)amino]benzylidene}-N'-(4-chlorobenzylidene)diaminomaleonitrileto N-(4-chlorobenzylidene)diaminomaleonitrile and4-diethylaminobenzaldehyde, followed by subsequent reaction of thelatter aldehyde with the starting monoanil N- 4-[N,N-bis-(ethyl)amino]benzylidene}diaminomaleomtrile. The ratio of cis and transproducts obtained does not change with longer reaction times, forexample, up to about 18 hours. However, when the condensation is carriedout with an increased amount of basic catalyst, for example, 0.50 moleof catalyst to one mole of monoanil, only the trans-symmetrical andtrans-unsymmetrical bisanils are formed. Using larger amounts of arylaldehyde, for example, greater than 2 moles per mole of monoanil, orusing other solvents does not sub- 5 stantially alter the product.

The major drawback of the above-described two-step process for preparingunsymmetrical bisanils of diaminomaleonitrile is that, under thereaction conditions, the product mixtures contain both symmetrical andunsymmetrical dyes. Due to the plurality of products capable of beingformed by this process, he transunsymmetrical dyes are generallyobtained only in product. Reaction times of about 4-17 hours can beemployed. Acid catalysts, such as sulfuric acid, hydrochloric acid,p-toluene-sulfonic acid and trifluoroacetic acid, can be used. Themonoanil can either be isolated moderate yields and complex separationmethods usu- 5 or the reaction mixture containing same can be used inally are necessary to effect satisfactory resolution of the the nextstep. product mixtures. An improved process (a preferred Reduction ofthe monoanil, for example, with sodium process herein) for thepreparation of trans-unsymmetborohydride, gives theN-benzyldiaminomaleonitrile rical bisanil adducts of diaminomaleonitrile(the prederivative in high yield. Reduction of the monoanil adfel'redadducts herein) is illustrated y the following duct is acritical featureof the improved process in that general scheme: it precludes theformation of undesirable mixtures dur- CN CN 0N C=C Ar CHO C=C NH NH Ar-HC= NH CN CN [Red '11. CN cu C=C C=C H N Ar HC N 2 Ar CH NH NH CN CNCN\ CN C=C Ar CHO C=C 2 Ar CH NH NH Ar CH NH N=CH-Ar CN CN [jgxm'm] C=CN=CH-Ar Ar CH NH 2 c1i\ on F CN N=CH-Ar 'T::''' 2 i i c=c CH Ar -HC=N CNl l 2 Ar 2 This four-step synthesis involves an initial condensation of1 mole of diaminomaleonitrile with a first aryl aldehyde to give themonoanil adduct. In practice, any organic solvent can be used in thisinitial step, ketones and aldehydes which can react withdiaminomaleonitrile being an exception. It is not necessary to have thediaminomaleonitrile in solution. Solvents which can be used in thiscondensation include tetrahydrofuran, ethyl Cellosolve,dimethylformamide, methanol, ethanol and mixtures thereof. A usefultemperature range is -80C.; however, a temperature of 30C. is preferredand provides the best yield and quality of ing the subsequentcondensation with Ar CHO (as was the case with the above-describedtwo-step process). Preferably, an organic solvent is present during thereduction step; included among the preferred solvents aretetrahydrofuran, methanol, ethanol and ethyl Cellosolve, the latterbeing especially preferred. The addition of sodium borohydride providesan exothermic reaction and external cooling is necessary to keep thereaction temperature within the preferred lO-35C. range. Above C. theproduct obtained is of poor quality. The sodium borohydride normally canbe added over a 20-40 minute period while still maintaining thetemperture below 35C. Other reducing agents, such as lithium aluminumhydride and lithium borohydride, can also be used. The amount ofreducing agent should be at least 0.50 mole per mole of monoanil toobtain complete reduction. The reduced monoadduct can be used withoutfurther purification in the next step of the reaction sequence. Thereduction works best when at least some alcoholic solvent is present inthe reaction mixture. Thus, the initial condensation ofdiaminomaleonitrile with Ar CHO in tetrahydrofuran (THE) to give themonoanil, as previously described, followed by addition of methanol tothe THF reaction mass and reduction of the monoanil with sodiumborohydride, provides high yields of reduced monoadduct. In addition, bycarrying out the initial condensation reaction at 2530C. rather than ator above the boiling point of tetrahydrofuran (6566C.), for example, at80C., and by keeping the subsequent reduction temperature below 25C.,excellent yields, for example, greater than 90% of theory, of thereduced monoadduct can be obtained.

Condensation of 1 mole of the reduced monoadduct with 1 mole of a secondaryl aldehyde Ar CHO provides the monoreduced bisadduct. This step canbe carried out with the same solvents and acidic catalysts used in theinitial monocondensation step. However, best results are obtained when asolvent such as methano] or ethanol is used. In such a solvent themonoreduced bisadduct is very insoluble and precipitates as formed. Room(ambient) temperature (2530C.) is preferred in this step for maximizingpurity of product; higher temperature cause the product to darkenconsiderably.

In order to obtain bisanil dyes having a red shade it is necessary, inmany cases, to have a dialkylamino group on at least one of the aromaticrings. It is preferred to add the appropriate dialkylaminobenzaldehydeas the second aryl aldehyde rather than as the first aryl aldehyde sincethe monoanil formed from such an aldehyde is, in some cases, not reducedcleanly by sodium borohydride.

Oxidation of the monoreduced bisadduct in the final step of thefour-step process with an oxidizing agent in an organic solvent providesthe desired unsymmetrical bisanil dye accompanied, in some cases, by thecolorless isomeric 2,3-dicyanoimidazole as shown in the aforesaidequations. The oxidation proceeds readily in tetrahydrofuran,acetonitrile, benzene, ethyl Cellosolve and acetone. However, in thesesolvents a large amount of imidazole is usually formed. Preferredsolvents which give the bisanil dye and little or none of the isomericimidazole are dimethylformamide, diemtylacetamide, dimethylsulfoxide,hexamethylphosphoramide and N-methylpyrrolidone. Oxidation at room(ambient) temperature (25-30C.) is preferred over elevated temperatures.Oxidizing agents that can be used include the nickel oxides, MnO PbO I Ndichlorodicyanoquinone and chloranil. Manganese dioxide gives the bestyield and purity of dye and is pre- NCH C ferred. In particular,carrying out the reaction with maganese dioxide in dimethylformamide at25-30C. for about 4 hours provides an yield of bisanil dye and the dyeis completely free of the isomeric imidaz ole. The bisanil dyestuff canbe conveniently isolated by adding tetrahydrofuran to the reactionmixture and filtering to remove insoluble manganese oxides, after whichisopropanol is added to the filtrate and the precipitated solids arefiltered off and washed with isopropanol; the precipitate is the desiredbisanil dye.

Alternatively, in order to eliminate tetrahydrofuran from the aboveprocedure, the reaction mass (after oxidation is poured into water and,after acidification, hydrogen peroxide or sulfur dioxide is addedthereto to dissolve the manganese oxides. The resultant mixture is thenfiltered and the crude dye thus obtained is washed thoroughly withisopropanol. The latter modification eliminates both the expensivetetrahydrofuran solvent and the tedious removal of the insolublemanganese salts, thus providing for a more economical process.

The geometry about the central carbon-carbon double bond of the bisanilprepared by the fourstep process is exclusively trans as evidenced bymeasurement of the dipole moment. Thus, the preferred four-step processaffords a high yield, for example, 70-80% overall fromdiaminomaleonitrile, of unsymmetrical transbisanil dyes uncombinatedwith the cis isomer or the isomer imidazole.

The symmetrical bisanil dyes previously discussed can also be preparedby the aforesaid four-step process but they are more advantageouslyprepared in good yield by the one-step process previously described.

As still another example of a process which can be employed herein is atwo-step process by which can be prepared symmetrical or unsymmetricalbisanil dyes, and particularly such dyes which have a predominantlytrans configuration. This process comprises heating diaminomaleonitrilein dimethylformamide under acidic conditions, preferably provided bysulfuric acid, with a molar equivalent of a first aryl aldehyde Ar CHOto produce a monoanil and then, employing the monoanil thus produced inplace of diaminomaleonitrile, repeating the procedure with a molarequivalent of either the first aryl aldehyde Ar,CHO or a second aryaldehyde AR CHO that is different from the first aryl aldehyde toproduce either the symmetrical or unsymmetrical bisanil dye. Thereaction times are very short, usually 1030 minutes, and water producedduring the condensation need not be removed to facilitate formation ofthe desired product. Although dimethylformamide is the preferred aproticsolvent, other solvents are useful, for example, dimethylacetamide,hexamethylphoramide, dimethylsulfoxide and N-methylpyrrolidone. Thecondensations are carried out in a temperature range of C. to theboiling piont of the solvent. The preferred range is l40-150C. Acidiccatalysts, other then sulfuric acid, which are useful in providingacidic conditions include hyrochloric acid, p-toluenesulfonic acid andtrifluoroacetic acid.

Preferred symmetrical bisanil dyes herein include:

C=C o c a cn Preferred unsymmetrical bisani] dyes herein include:

The crude wet dye from any of the above processes is convenientlyconverted into a commercially usable form by mixing the crude dye, forexample, ten parts on a 100% basis, with about 2.5 parts of a ligninsulfonate dispersant and water in a colloid or sand mill. Milling iscontinued until a fine, stable aqueous dispersion or paste is obtained,that is, until dye particle size is reduced to approximately one micron(average size).

Both the symmetrical and unsymmetrical bisanil dyes posess hightinctorial strengths and provide, on polyester, extremely bright,fluorescent yellow to blue dyeings having generally good fastness tosublimation and moderate fastness to light. These dyes are especiallyuseful for dyeing and printing polyester where bright shades aredesired. Because of the chemical versatility inherent in the preparativemethods disclosed herein and because of the very high tinctorialstrengths and breadth of shades obtainable, the bisanil dyes can be usedin such a way as to suppress very undesirable coloration featureswithout paying a color value penalty.

Experiment 1 Aqueous (Pressure) Dyeing Procedure Five grams ofcommercially available polyester fabric were placed in an autoclavecontaining:

an aqueous dye paste (15% active ingredient containing the dye ofExample 4 0.1 gram an anionic long chain sodium hydrocarbon sulfonate(10% solution) 1.0 ml.

a nonionic long chain alcoholethylene oxide adduct (10% solution) 0.5ml.

ethylene diaminetetraacetic acid,

sodium salt (1% solution) 1.25 ml.

butyl benzoate carrier (10% solution) 1.5 ml.

water to 75 ml.

acetic acid to adjust the pH to 5.5.

The contents of the autoclave were heated for 1 hour at 265C. The dyedfabric was then rinsed in water and 30 dried. The polyester fabric wasdyed an extremely bright, fluorescent red shade.

Experiment 2 Thermosol Procedure A pad bath was prepared containing:

an aqueous dye paste (15% active ingredient) containing the dye ofExample 50 grams purified natural gum thickener 20 grams water to lliter.

The pad bath was padded on commercially available 65/35 polyester/cottonfabric with a pickup of 5065%, based on dry fabric weight (owf),followed by drying (infrared predrying followed by hot air or hot candrying is preferable) to remove the water. Thermosoling, by which thepolyester component was dyed with the disperse dye, was accomplished byheating the dried pigment-padded fabric for 90 seconds at 213C. Unfixedsurface dye, on either the polyester or the cotton or both, was removedby padding the fabric from an aqueous bath containing 50 g./1. of sodiumhydroxide and 40 g./l. of sodium hydrosulfite at 2739C., followed bysteaming for 30 seconds. The fabric was then rinsed in water at 27C.,scoured for 5 minutes at 93C.

in water containing 1% ether alcohol sulfate detergent, 5

rinsed in water at 27C. and then dried. After dyeing and cleaning, thematerial was then padded (for permanent press treatment) with a pickupof 50-65% (owf) with a bath containing:

a dimethyloldihydroxyethyleneurea cross-linking agent 200.0 ap-octylphenoxy(C H,O) H wetting agent 2.5 a dispersed acrylicthermoplastic binding agent 22.5 a nonionic, paraffin-free, polyethyleneemulsion which serves as a fabric softener 22.5 a nonionic polymeremulsion which imparts luster. a silky hand and antistatic properties tothe fiber 30.0 a 20% aqueous zinc nitrate curing catalyst 36.0

The resin-impregnated material was air dried to remove the water andthen cured at 163C. for 15 minutes. The durable-press treatedpolyester/cotton fabric was dyed an attractive, bright, fluorescentscarlet shade.

The following examples are given to illustrate the preparation of thebisanil dyes described above. All parts are given by weight unlessotherwise noted.

Example 1 Preparation of Symmetrical Bisanil A mixture of 2.16 parts ofdiaminomaleonitrile, 9.16 parts of4-[N,N-bis(cyanoethyl)amino]benzaldehyde, 0.2 part of p-toluenesulfonicacid, 30 parts of dimethylacetamide (DMAC) and 150 parts of benzene washeated at 90C. while benzene plus water was removed by distillation.After distillation for 17 hours, the remaining benzene was removed bydistillation under nitrogen. After cooling the DMAC solution to -5C. 4.2parts of red bisanil were collected by filtration; its m.p. was 2l8220C.Thin layer chromatogra' phy on silica gel-coated glass plates usingbenzene-' acetonitrile (4:1) as eluent showed one scarlet spot at an R,of 0.1. Calcd. for C H N C, 68.6; H, 5.0; N, 26.5%. Found: C, 68.2; H,5.4; N, 26.5%. An infrared spectrum of a Nujol mull of the productshowed no N-H absorption at 2.8-3.1 t. Based on the above, the productwas of the structure The mother liquor from the aforesaid filtration waspoured into a large volume of ice-cooled water and the precipitatedsolids were isolated by filtration, washed with water and dried to give3.9 parts of a red solid, mp. l-186C. Thin layer chromatography showedthe presence of a minor scarlet spot at an R; of 0.1 and a major yellowspot at an R; of 0.6. The product showed absorption bands at 515 my.(a,,,,,,, of 10 liters g. emf) for the bisanil and at 410 my. (a of 87liters gfcmf) for the monoanil formed by hydrolysis of the bisanilduring the DMF treatment. Calcd for C H N C, 68.6; H, 5.0; N, 26.5%.Found: C, 67.0; H, 5.7; N, 29.5%. Thus, hydrolysis of the bisaniloccurred to provide a mixture comprising a preponderance of the monoaniland a minor amount of the bisanil.

Example 2 Preparation of Symmetrical Bisanil A similar result wasobtained by starting with the appropriate monanil derivative of insteaddiaminomaleonitrile.

Example 3 Preparation of Unsymmetrical Bisanil by a Two-Step Process a.A mixture of 132 parts of diaminomaleonitrile, 210 parts of4-[N,N-bis(ethyl)amino]benzaldehyde, 30 drops of concentrated sulfuricacid and 2,000 parts of tetrahydrofuran (THF) was heated at 65C. for 3hours. The tetrahydrofuran was partially evaporated and 1,000 parts ofethanol were added. The precipitated solids were isolated by filtrationand air dried to give 227 parts of yellow monanil (76% yield). A mixtureof 14.1 parts of 4-chlorobenzaldehyde, 20 drops of piperidine and 500parts of benzene was heated at 8090C. while continuously azeotroping thewater formed during the reaction. The monanil (13.4 parts) was thenadded in portions over a 6-hour period and heating at 8090C. wascontinued for an additional 2 hours. The solvent was removed bydistillation and the resultant solid residue was boiled with 200 partsof isopropanol. After filtration and drying, 9.2 parts (47% yield) ofred product were obtained, m.p. 207208C. Thin layer chromatographyshowed the major component to be the unsymmetrical dye along with smallamounts of purple impurities. The dye had an absorptivity (a,,,,,, of177 liters gfcm. at a wavelength (A of 528 mu. Calcd. for C H N Cl: C,67.8; H, 5.2; N, 18.0%. Found: C, 68.6; H, 5.6; N, 17.9%. Based on theabove, the dye was of the structure b. A mixture of 6.7 parts of themonoanil of part (a), 7.05 parts of 4-chlorobenzaldehyde, 0.85 part ofpiperidine and 250 parts of benzene was heated at 8090C. for 1 hourwhile continuously azeotroping the water formed during the reaction.Thin layer chromatography of the reaction mixture showed the presence ofapproximately equal amounts of the trans-symmetrical and -unsymmetricalbisanil dyes; only traces of cisbisanil dyes could be detected.

0. When the condensation was run on the same scale but in the presenceof only 1 drop of piperidine, the major products after 1 hour at 8090C.were the cissymmetrical and -unsymmetrical bisanil dyes. Only traces oftrans-bisanil dyes were present.

Example 4 Preparation of Unsymmetrical Bisanil by a Four-Step Process Amixture of 21.6 parts of diaminomaleonitrile, 38.3 parts of4-bromobenzaldehyde, 5 drops of concentrated sulfuric acid and 250 partsof tetrahydrofuran was stirred at 25-30C. for 4 hours. Methanol (100parts) was added and 7.95 parts of sodium borohydride were added inportions over a 20-minute period while maintaining the temperature at2025C. by external cooling in ice water. After stirring for minutes at25C. most of the solvent was removed by distillation. The remainingsolution was poured into 1,500 parts of ice-cooled water and stirred for1 hour; the resultant solids were collected and air dried to give 53.5parts (97% yield) of the reduced monoadduct. This material was used inthe next step of the reaction sequence without purification.

A slurry of 53 parts of the reduced monoadduct, 38.8 parts of4-[N,N-bis(ethyl)amino]benzaldehyde, 1.2 parts of concentrated sulfuricacid and 1,000 parts of ethanol was stirred for 4 hours at 2530C. Thereaction mixture was filtered and the collected solids were air dried,yielding 83 parts (99% yield) of orange reduced bisadduct. This productwas of sufficient purity to use in the next reaction withoutpurification.

A mixture of 82 parts of the reduced bisadduct, parts of manganesedioxide and 500 parts of dimethylformamide was stirred for 4 hours at2530C. Tetrahydrofuran (500 parts) was added and the resulting mixturewas filtered through a medium porosity, sintered glass funnel. Thesolids thus obtained were washed with four 400-part portions oftetrahydrofuran to dissolve and separate the precipitated bisanil dyefrom the insoluble manganese oxides. The combined tetrahydrofuranfiltrates were concentrated under reduced pressure to a thick slush; 600parts of isopropanol were added and the resultant slurry was filtered;the collected solids were washed with three 100 -part portions ofisopropanol to give 61.5 parts (75.6% yield) of bisanil dye, as metallicgreen flakes, exhibiting an absorptivity (a,,,,,, of 153 liters gfcmf ata wavelength (M of 531 mp.. Recrystallization of the product frombenzene gave very dark needles, m.p. 205206C.; it exhibited an a of 166liters gfcm? at a)t,,,,,, of 531 my. Calcd. for C H N Br: C, 60.8; H,4.7; N, 16.1%. Found: C, 59.5; H, 4.8; N, 15.6%. Thin layerchromatographic analysis of the product showed only a single purplespot. Based on the above, the dye was of the structure.

Example 5 Preparation of Unsymmetrical Bisanil by a Four-Step Process Amixture of 10.8 parts of diaminomaleonitrile, 15.6 parts ofl-naphthaldehyde, 5 drops of concentrated sulfuric acid and parts oftetrahydrofuran was stirred at 2530C. for 17 hours. Methanol (35 parts)was added and the solution was cooled to 15C. Sodium borohydride (3.8parts) was added in portions while maintaining the temperature between15 and 20C. by external water-ice cooling. After stirring for 15minutes, the solution was poured into 1,500 parts of icecooled water andstirred for 3 hours; the solids (the reduced monoadduct as a light tanpowder) were removed by filtration.

A slurry of the reduced monoadduct, 18 parts of 4-[N,N-bis(ethyl)amino]benzaldehyde, 15 drops of concentrated sulfuricacid and 200 parts of ethanol was stirred for 17 hours at 25-30C. Thesolids were isolated by filtration, yielding 35.4 parts of the reducedbisadduct as an orange powder A mixture of the reduced bisadduct, 35parts of manganese dioxide and parts of dimethylformamide was stirredfor 5 hours at 25-30C. The solids were isolated by filtration and washedwith four 400-part portions of tetrahydrofuran to give a solution of thedesired bisanil dye. The tetrahydrofuran and dimethylformamide weredistilled off under reduced pressure and the solids thus obtained werewashed with ispropanol and dried, yielding 32.5 parts (80% yield) ofbisanil dye as a dark red powder, m.p. 211213C.; it exhibited anabsorptivity (a,,,,,,. of 183 liters g. cm? at a wavelength (X of 540mu. Calcd. for C H N C, 77.0; H, 5.7; N, 17.3%. Found: C, 76.3; H, 5.6;N, 17.4%. Thin layer chromatography showed only a single purple spot.Based on the above, the dye was of the structure poured into 800 partsof water containing parts of aqueous ammonium hyroxide. After stirringfor 1 hour,

EXAMPLE 6 Preparation of Unsymmetrical Bisanil by a Four-Step ProcessExample 5 was substantially repeated except that another solvent wasused in placed of tetrahydrofuran in both the reduction and oxidationsteps. To a slurry of 12.7 parts of the monoanil of Example 5 in 50parts of ethyl Cellosolve was added in portions, 0.95 part of sodiumborohydride while maintaining the temperature at 35C. by externalcooling in ice-cooled water. The resulting solution was stirred for 30minutes, poured into 500 parts of ice water and stirred for 1 additionalhour. The light tan precipitate was collected by filtration and airdried to give 12.4 parts (100% yield) of reduced monoadduct.

The reduced monoadduct was condensed with 4-[N,N-bis(ethyl)amino]benzaldehyde in ethanol as described in Exapmle 5to yield the reduced bisadduct.

A mixture of 5.0 parts of the reduced bisadduct, 5.0 parts of manganesedioxide and parts of dimethylformamide was stirred for 2 hours at 2530C.The solution was poured into 350 parts of ice-cooled water and 9 partsof concentrated sulfuric acid were added. Hydrogen peroxide (6 parts ofa 30% aqueous solution) was added in portions to dissolve the manganeseoxides. The resulting mixture was filtered and the crude dye thusobtained was washed with two 50-part portions of isopropanol and driedto give 4.5 parts (89.4% yield) of the bisanil dye, as a red solid,exhibiting an absorptivity (a of 169 liters gf'cm. at a wavelength (A of540 mu. Thin layer chromatography showed only a single purple spot; theR, was identical to that of the dye of Example 5.

Example 7 Preparation of Unsymmetrical Bisanil by a Four-Step ProcessThe dye of Example 4 was also prepared by reaction of the reducedbisadduct (9.6 parts) with 10.6 parts of lead dioxide (0.04 mole) in 200parts of acetonitrile at 55C. for 9 hours. The suspended lead sludge wasfiltered off and the solvent was evaporated. Thin layer chromatographyshowed the residue to consist of approximately equal amounts of theunsymmetrical bisanil dye of Example 4 and the colorless isomericimidazole. The imidazole was removed by prolonged extraction of thesolid with hot (8090C.) ethanol; the extracted product was shown by thinlayer chromatography to consist of a single purple spot. The analyticaldata obtained on the product was substantially the same as that reportedin Example 4.

Example 8 Preparation of Symmetrical Bisanil A mixture of 9.4 parts of4-[N,N-bis(ethyl)amino]- benzaldehyde, 2.16 parts ofdiaminomaleonitrile, 4.0 parts of phosphorus pentoxide, 6 drops ofconcentrated sulfuric acid and 70 parts of hexamethylphosphoramide wasstirred at 5055C. for 6 hours. After each 2-hour period, an additional1.0 part of phosphorus pentoxide was added. The reaction mixture wasthen the precipitated solids were collected by filtration, washed withwater and dried to yield 5.5 parts (65% yield) of symmetrical bluish-redbisanil, m.p.140142C. The product was recrystallized three times fromisopropanol, providing an analytically pure sample, m.p. 162-l 65C. Theproduct exhibited a high intensity absorption band liters gfcmf) at awavelength of 558 my and, in addition, two lower in tensity bands at 400my. (61.5 liters g. cm) and 382 mp. (56 liters gfcmf Based on thepresence of the lower wavelength absorption bands and the large observeddipole moment of 14.6 Debye, the product was confirmed as having cisgeometry about the central carbon-carbon double bond. Based on theabove, the structure is p(H C NC H CH- =NC(CN)#I(CN)N=CH--C H -pN(C HEXAMPLE 9 Preparation of Symmetrical Bisanil A mixture of 10.8 parts ofdiaminomaleonitrile, 29.0 parts of indole-3-carboxaldehyde, 400 parts oftetrahydrofuran and 10 drops of concentrated sulfuric acid was stirredat 65C. for 16 hours. The tetrahydrofuran was partially evaporated and10 parts of 10% aqueuos sodium carbonate were added. The precipitatedsolids were isolated by filtration, washed with water, then withisopropanol and dried to give 20.3 parts of yellow monoanil (86% yield),m.p. 227.5-229C.

A mixture of 14.1 parts of the monanil, 12.0 parts of concentratedsulfuric acid, 11.6 parts of indole-3-carboxaldehyde and 150 parts ofdimethylformamide was heated in about 10 minutes to 150C.; it wasmaintained at this temperature for 20 minutes. The reaction mixture wasthen poured into 1,000 parts of water. The precipitated solids werecollected by filtration, washed with water, then with isopropanol anddried. The product was recrystallized three times fromacetonitrile-chloroform to give 6.85 parts (31.7% yield) of thesymmetrical yellow bisanil, m.p. 331333C. The dye had an absorptivity (aof 220 liters gfcmf at a wavelength (X of 480 mu. Calcd. for C H N C,72.9; H, 3.9; N, 23.2%. Found: C, 71.4; H, 4.3; N, 22.3%. Based on theabove, the structure of the dye is Example 10 Preparation ofUnsymmetrical Bisanil A mixture of 4.7 parts ofindole-3-carboxaldehydediaminomaleonitrile monoanil, 3.54 parts of 4-[N,N-bis(ethyl)amino]benzaldehyde, 4.0 parts of concentrated sulfuricacid and 50 parts of dimethylformamide was heated at 145l50C. for 20minutes. The

reaction mixture was then poured into 1,000 parts of water. Theprecipitated solids were filtered off, washed with water and dried. Thinlayer chromatographic analysis showed the presence of the two possiblesymmetrical bisanil condensates, together with a third brightreddish-orange component. The latter material was isolated from theproduct mixture by column chromatography on Florisil using chloroform aseluent. After two recrystallizations from acetonitrile, a small amount(0.10 part) of the pure unsymmetrical bisanil condensate was obtained,m.p. 265268C. lnfrared analysis showed an NH band at 3395 cm. and CNabsorption at 2200 cm. and 660 emf. The visible absorption spectrumexhibited a k of 522 mu and an a of 239 liters g.cm.. Based on theabove, the structure of the dye is The isomerization of the cis dye ofExample 8 to the trans form of this example was readily effected byheating the former dye in benzene containing a small amount of iodine.The resultant product was identical in m.p. and spectral properties tothe trans isomer.

Examples 12-1 18 Symmetrical bisanil dyes were prepared (Examples 12-19)by procedures similar to that described in Example 2. Unsymmetricalbisanil dyes were prepared (Examples 20-118) by preferred four-stepprocesses similar to those described in Examples 4 and 5. Data for thedyes produced are shown in Table II. Except as snoted below thesubstituents A, B, c, X, Y and Z appearing as column headings in thetable correspond to the substituents shown in the formula A (50( (2)cu-n--c(cm)=c(cn)--n-ca a Ew (6)2 5) Y The groups shown in column Y forExamples 34, 39,

Example 11 Preparation of Symmetrical Bisanil 82, 87, 88 and 95correspond to the entire group A mixture of 2.16 parts ofdiaminomaleonitrile, 3.5 parts of 4-[N,N-bis(ethyl)amino]benzaldehyde,8.0

parts of concentrated sulfuric acid and 50 parts of di- Xmethylformamide was stirred at l45-l50C. for 20 40 minutes. The reactionmixture was then poured into Y 1,000 parts of water; the precipitatedsolids were collected by filtration, washed with water and dried. Theproduct was purified by column chromatography on Florisil usingchloroform as eluent, yielding 0.47 part of Similarly, the groups shownin column B for Examples bluish-red bisanil, m.p. 265-268C. It exhibitedan ab- 27 31 49 50 52 53 55 1 2 4 66, 70, 76 Sorptivity 111111.) Of 265liters at a Wavelength 78-83, 8999 and 118 correspond to the entiregroup of 561 mu. A nuclear magnetic resonance (NMR) spectrum of theproduct was found to be identical to that of the dye of Example 8.However, the absence of 5 A any lower wavelength absorption, togetherwith the much higher melting point and a low observed dipole moment of3.2 Debye indicates that the product is actually the trans form of thedye of Example 8.

Elemental Analysis Found TABLE ll-continued (4)-N(CH,)C H CN (4)-Cl H(4)N(CH;,)C H.CN

a Shade on Calculated l.g."cm.") Polyester C H Yellow 58.4' 205 Bluish74.5

Red 159 Greenish 69.8

Yellow 170 Yellow Red 171 Bluish Red 223 Bluish 60.2 4.6

Red 194 Red l4] Bright Orange 168 Orange 65.9 4.2

MI-t p) Example Example Example HHHHHHHHHH 973 1 66 Z HH HH H H .HH N&22 a7 a7 on 4 6 22 ll ll 1 5 22 0 w 344 65 56 5 44 F .m m M. 0 54 58 589 58 N 4 m C 33 46 87 9 2 O N s h Q 1 la H Hh) w l a H H l HHH v. H .1;NN n h C C C mwChmPhY c e N 3 .3 30 3 31 hhm ln d. .m I ll mmm um u numm m an mm mm um mm wmm mm wmwwwwwwwwm E wwm www wmwwww NNNNNNNNNN w NN.NN N N NN 1. Z 1 m .2 5 1. 1 ,m EFL; uwmumwommmm w 344 6s 5s 5 44 vMomma momma m w m C H mm HHHH HH HH C .12 32 .1 l 05 X HH H H H. 44 4 93 8 )l 2 Z 66 77 67 7 76 2 22 MM Be ewe J HHHH HHH m. mmm emwww wmm n CHJH HH H H .HH m1 RR RRmR e m W $0 00 0Y0 W a m d m m m 0 GO HH HHmHHH.m5 5 mw mm B HRH 4H HH a 111 11 1 11 1M1 N. 2 2 w 4 34 z z I H Ol ll c 1c cc N 0 Ha. NW0 57 0 w 80 N F HHH u 1d 55$ an no 5 m A .1 H t k e P W.234567890 m0 234 56 78 9 0 m0 234 56 390 2222222233 3N 222 22 22 2 33333 33 3 3344 X E E Shade on Polyester Violet Bright Bluish Red BluishRed Violet Bright Orange Bright Orange Brl ht Bluish Red ll! (my)Example No.

TABLE ll-continued Elemental Analysis Example A... a, Shade onCalculated Found No. (my) (1.g."cm. Polyester C H N C H N 39 460 121Reddish 61.3 2.8 17.8 59.8 2.7 18.5

Yellow 523 154 Bright 67.2 6.0 19.6 67.3 5.2 19.2

Orange 41 520 153 Bright 67.2 6.0 19.6 67.2 5.1 19.4

Orange Example No. A B C X Y Z 42 H (3')Cl H H (4)N(C,H;,) H 43 (2)Cl HH H l )N( z 5) H 44 H H H (2)Cl (4)N(CH;,), H H (4')Cl H (2)C1(4)-N(CH=) H 46 (3')Cl (4)C1 H H (4)-N(C,H H 47 (3')Cl (4')-Cl H (2)CH(4)N(C,H,)C,H CN H 48 (2') -c| (6)NO H H (4)-N( sl: H 49 l-naphthyl2)-cHa (4)-N( 5) 4 H l-naphthyl H (4)N(CH,CH,CH,CH H

Elemental analysis Example X an. Shade on Calculated Found (mu)(l.g."cm.) Polyester C H N C N 42 533 152 Bright 67.8 5.2 18.0 68.0 5.317.4

Red 43 540 118 Bright 67.8 5.2 18.0 68.0 5.5 17.4

Red 44 510 145 Orange 66.4 4.5 19.3 64.7 5.1 17.1 45 519 148 Orange 61.13.8 17.6 61.2 5.4 12.1 46 540 157 Bright 62.2 4.5 16.5 60.7 4.6 15.6

Bluish Red 47 518 162 Scarlet 48 550 139 Violet 60.8 4.4 3 60.9 4.4 19.149 527 158 Scarlet 75.4 5.4 18 9 76.2 5.8 17.8 50 540 146 Red 78.1 6.877.7 6.7 14.8

Example No. A B C X Y Z 51 (2)Cl H (6')Cl (2)CH (4)N(C,H H 52 l-naphthyl(2)CH, (4)N(C H H 53 l-naphthyl H (4)-N(C,H )C,H H

OCOC H 54 (2)C1 H (6')C1 H (4)N(C,H )C,H,- H

OC H 55 Z-quinolinyl H (4)-N(C,H,), H 56 H (3')CN H H (4)-N(C,H H

Elemental Analysis Example A. a Shade on Calculated Found No. (mu)(l.g."em.") Polyester C H N C H N 51 545 138 Violet 63.0 4.8 15.9 58.54.9 15.8 52 545 170 Bright 77.3 6.0 16.7 77.3 6.1 16.6

Bluish Red 53 527 138 Scarlet 75.5 5.2 13.3 75.0 5.3 12.1 54 527 115Scarlet 64.0 4.3 12.9 63.8 4.4 12.8 55 551 198 Bright 74.9 5.5 20.7 74.45.5 20.8

Bluish Red 56 535 167 Bright 72.6 5.3 22.1 73.0 5.6 22.3

Bluish Red Example No. A B C X Y Z 57 (2)NO; (4') N H a s): H 58 (3')Br(4')-OCH (5')OCH, H (4)N(CHs)z H 59 (2)0H ')B ($')-Br H s)z H 60 (3')Cl(4)Cl H (ll-CH: z a): H 61 2-thienyl H s): H 62 Z-hydroxy-l- H s): H

naphthyl 63 (2)F H H H (4)-N(C,H,), H

Elemental Analysis Example A. a,.,,,, Shade on Calculated Found No. (mu)(1.g."cm.") Polyester 1 C H N C H N 57 590 Blue 60.1 4.6 21.3 60.5 4.720.3 58 532 Bright 58.3 4.9 14.2 59.3 5.0 14.3

Scarlet 59 560 107 Bright 50.0 3.6 13.2 49.9 3.7 12.9

Violet 60 545 171 Bright 63.0 4.8 16.0 63.1 4.8 16.1

Bluish Red 61 532 192 Bright Red 62 550 196 Violet 73.8 6 0 16.5 75.15.4 17.1 63 532 186 Bright 70.8 5 4 18.7 71.0 5.1 18.8

Red

alkylene-CN, CO A, OCOA, OCONHA or CO C alkylene-OCOA;

d. R, is CN, halogen, OH, phenyl, OC alkylene-CN, CO A, OCOA, CO Calkylene-OCOA, 50 A,

phthalimido, succinimido, glutarimido, OCOCH=CH CH CH(OCOA)CH OA or CHCH(OCONHA )CH OA;

h. R is C alkyl, C H OH, C cycloalkyl or R which process comprisesheating diaminomaleonitrile and at least two molar equivalents of thearomatic aldehyde Ar CHO in the presence of glacial acetic acid toproduce the symmetrical/ dye of the formula 2. Process of claim 1wherein the reaction is carried out at ll5l20C. for about 4 hours andthe molar ratio of aromatic aldehyde to diaminomaleonitrile is about2:1.

3. Process of claim 2 wherein the aromatic aldehyde is4-[N,N-bis(ethyl)amino]benzaldehyde and the symmetrical bisanil dyeproduct is

1. ONE-STEP PROCESSOF PREPARING THE SYMMETRICAL BISANIL DYE FORMULAAR1CH=N-C(CN)=C(CN)-N=CH-AR2 WHEREIN AR1 AND AR2 ARE THE SAE AND ARESELECTED FROM PHENYL AND NAPHTHYL GROUPS CONTAINING 0-3 SUBSTITUENTSSELECTED FROM NO2, HALOGEN, CN, C1-4 ALKYL, C1-4 ALKOXY, OCH2PHENYL,PHENYL, CF2, OH, OC1-4 ALKYLENE-N(C1-4ALKYL)2, C2-4 ALKYLENE-CI,NHCONH2, NHCOA, NHSO2A, SR8, SO2R8, NHR, NHCOC1-4 ALKYLENE-B AND -NR1R2WHEREIN A. R1 IS C1-4 ALKYL OR C2-4 ALKYLENE-R3, B. R2 IS C1-4 ALKYL,C2-4ALKYLENE-R4 OR, IF AR, OR AR2 IS PHENYL C3 ALKYLENE ATTACHED TO APHENYL POSITION WHICH OR ORTHO TO THE POSITION TO WHICH THE NITROGEN ISATTACHED, C. R3 IS CN, HALOGEN, OH, PHENYL, C1-4 ALKOXY, OC1-4ALKYLLENE-CN, CO2A, OCOA, OCONHA OR CO2C1-4 ALKYLENEOCOA, D. R4 CN,HALOGEN, OH, PHENYL, OC1-4 ALKYLENE-CN, CO2A, OCOA, CO2C1-4ALKYLENE-OCOA, SO2A, PHTHALMIDO, SUCCINIMIDO, GLUTARMIDO, OCOCH=CH2,CH2-CH(OCOA)CH2OA OR CH2CH(OCONHA)CH2OA, E. A IS C1-4 ALKYL OR R5, F. BIS HALOGEN, C1-4 ALKOXY OR R5, G. R5 IS PHENYL CONTAINING 0-2SUBSTITUTENTS SELECTED FROM C1-4 ALKYL, C1-4 ALKOXY,HALOGEN, NO2, CN,C1-4 ALKYL CONH AND NR6R7 WHEREIN EACH OF R6 AND R7 IS INDEPENDENDENTLYSELECTED FROM H AND C1-4 ALKYL, WITH AT LEAST ONE OF R6 AND R7 BEINGC1-4 ALKYL, AND H. R8 IS C1-4 ALKYL, C2H4OH, C5-6 CYCLOALKYL OR R5,WHICH PROCESS COMPRISES HEATING DIAMINOMALECONITRILE AND AT LEAST TWOMOLAR EQUIVALENTS OF THE AROMATIC ALDEHYDE AR1CHO IN THE PRESENCE OFGLACIAL ACETIC ACID TO PRODUCE THE SYMMETRICAL/DYE OF THE FORMULAAR1CH=N-C(CN)-N=CH-AR2.
 2. Process of claim 1 wherein the reaction iscarried out at 115*-120*C. for about 4 hours and the molar ratio ofaromatic aldehyde to diaminomaleonitrile is about 2:1.
 3. Process ofclaim 2 wherein the aromatic aldehyde is4-(N,N-bis(ethyl)amino)benzaldehyde and the symmetrical bisanil dyeproduct is